There is a web form to paste your code into and it will return your converted AS3 code (check it here).
There is also an command line exe in the zip file
I’m not very good at command line, so for your (and mine) convenience I will explain how to get the exe to work with a .BAT file (I work on a PC so the example only works on PC).

Download the zip file and extract it somewhere on your computer. In my case C:\tmp\convert
I’ve created to folders in the convert folderC:\tmp\convert\input
C:\tmp\convert\output
and in the input folder I copied all the classes I’ve ever written.

Now create a file with a .BAT extension (in my case convert.bat) and it doesn’t matter where you put it, but I put it next to the convertas2as3.exe in C:\tmp\convert folder.

Open the file you just created and paste this in there:
pause
C:\tmp\convert\convertas2as3.exe -input "C:\tmp\convert\input" -output "C:\tmp\convert\output"

or adjust the path to the files you want to convert
save the file and open the .BAT file (in my case convert.bat) and all your classes you ever have written are converted to AS3…

Well as good as it get’s: it’s not 100 percent converted to AS3 but it helps you with most of your code, and helps you on your way to find the correct code.

example
take the code I translated in the previous post but now in a class file:

I finally started programming with ActionScript 3 (AS3); I know, I not a early adopter… 😉

And the first steps in AS3 are as uncomfortable as the first time I started OOP programming … or when I started moved from AS1 to AS2…

Since I started working for NOISE 5 months ago and moved to Amsterdam, I haven’t had time to do learn AS3.
That luckily has changed 🙂 and I started learning the basics.

And the first obstacle I ran into was something very simple: I always use a basic document (FLA) with default library items, some layers I always use and some ActionScript code to align the stage:
_root._quality = "BEST";
Stage.scaleMode = "noScale";
Stage.showMenu = false;
Stage.align = "TL";
stop ();

I have this also in a class (AS2), so I thought it would be useful to rewrite this class in AS3.
and I wanted to use this in my new as3 files too… (remember that this is the first thing a tried)